This essay aims to provide a philosophical analysis of the Chinese concept of cheng (sincerity) as a political virtue that could be incorporated to ground a duty of civility in liberal deliberative democracy. It is argued here that the virtue of sincerity is an essential feature of the liberal political culture taken for granted by Rawls in his theory of public reason. Ideal procedures and public discourse are not sufficient to generate civic virtues. The goal of this essay is to show how, in the Chinese conception, the root of civility lies in the virtue of Cheng, which can provide the moral grounding for a duty of civility that is essential to sustaining the stability and overcoming the problem of defection from support of the common good in pluralistic states.